1. Field of Invention
The present invention relates to a power feed connector for an electric automobile, and relates in particular to a waterproof structure for a connector, including a waterproof sealing member that is closely attached to a power line that moves back and forth as the connector is engaged and disengaged.
2. Related art
FIGS. 6 and 7 are diagrams showing the waterproof structure of a conventional connector.
This structure is applied, for example, for a power feed connector for an electric automobile. As is shown in FIG. 6, a butt terminal 73 is slidably retained inside a synthetic resin connector housing 72 by the urging force exerted by a coil spring 74, and a power line 75, attached by a pressure connection to the terminal 73, is inserted into and slides through a hole 77 in a ring-shaped waterproof rubber plug (waterproof sealing member) 76.
The terminal 73, which has a substantially cylindrical shape and which is urged forward, i.e., in the connector engagement direction, by the coil spring 74, so that its distal end is held against a synthetic resin front holder 80 fitted over the distal end of the connector housing 72, forms an electrical connection with a terminal 79 of a connector 78 when its; distal end face abuts against the terminal 79. Ring-shaped waterproof packing 82, which is fitted around the distal end of a cylindrical, electrical contact portion 81 of the terminal 73, forms a seal with the inner wall of a terminal chamber 83.
A cylindrical press-fitting power line contact 84, which is integrally formed at the rear of the electric contact portion 81 of the terminal 73, is connected to the conductive portion of the terminal of the power line 75, which is closely attached to sealing lips around the inner diameter of the hole 77 in the rubber plug 76 through which it slides longitudinally. The rubber plug 76, which is formed using oil impregnation and which is positioned inside a hole 85 in the connector housing 72., is securely held in place by a synthetic rear holder 86, and sealing lips on its outer surface are closely attached to the inner fade of the hole 85. The connector housing 72, the waterproof rubber plug 76 and the holders 80 and 86 constitute a connector 71.
As does the connector 71, the other connector 78 includes at the least a synthetic resin connector housing 87 and a terminal 79. This terminal 79 also has an electric butt contact portion 88 having a substantially cylindrical shape and a press-fitting power line contact 89. The connector 78 itself is applied, for example, as a power reception connector mounted in an automobile.
As is shown in FIG. 7, when the connector 71 engages the connector 78, the terminal 73 is driven rearward to a retracted position by the terminal 79 and the coil spring 74 is compressed, while at the same time, the power line 75, which is moved to the rear and to a retracted position with the terminal 73, slides along the sealing lips on the inner diameter side of the hole 77 in the waterproof rubber plug 76. In this state, the distal end face of the terminal 73 is held tightly against the distal end of the terminal 79, forming an electrical connection between the power feed connector 71 and the power reception connector 78 and enabling the charging of the battery of an automobile to be begun.
When the charging is completed, the connector 71 is disengaged from the connector 78, disconnecting the terminal 73, which is driven forward by the urging force exerted by the coil spring 74, from the terminal 79, while at the same time, the power line 75, which is moved forward with the terminal 73, slides in contact with the sealing lips on the inner diameter side of the hole 77 in the waterproof rubber plug 76.
However, when the conventional structure is applied, especially as a power feed connector for an electric automobile, the connectors are frequently engaged and disengaged, so that the oil retained in the waterproof rubber plug (waterproof sealing member) 76, through which the power line 75 slides, is gradually consumed. Thus, as the friction is increased, there is a tendency for the abrasion or the cracking of the sealing lips on the inner diameter side of the hole 77 in the waterproof rubber plug 76 to occur. When this happens, water or dust may enter the connector 71 along the power line 75.
To resolve this problem, it is one objective of the present invention to provide for a connector a waterproof structure that can prevent the abrasion of the waterproof sealing member of the connector, along which a power line slides as connectors are engaged and disengaged, and that can enhance the waterproof and dustproof properties of the connector.
To achieve the above objective, in accordance with the invention, a waterproof structure is provided for a connector wherein a terminal to which a power line is attached is retained in a connector housing and a waterproof sealing member is disposed between the connector housing and the power line; wherein the front of the waterproof sealing member is secured to the power line and the rear of the waterproof sealing member is secured to the connector housing; and wherein a stretch portion is formed between the front and the rear of the waterproof sealing member.
It is also effective for a reinforcement portion to be internally formed between the front and the rear of the waterproof sealing member.
Further, it is effective, when the stretch portion is extended, for the front of the waterproof sealing member to abut against the wall of the connector housing, and for the;rear to abut against a rear holder attached to the connector housing.
In addition, it is effective for the waterproof structure for a connector of the present invention to be applied for a power feed connector.